Making A Big Discovery With Tiny Fossils

“I was given a piece of 100-million-year-old sedimentary rock,” Kimura recalls of her visit to a museum in her native Japan. “I could not imagine how many stories this stone had experienced through 100 million years.”

As a field assistant on an international expedition to a fossil site in Inner Mongolia, Kimura helped collect fossils smaller than a grain of rice. Guided by SMU Professor of Paleontology Louis Jacobs, Kimura identified the 17-million-year-old fossils as a new species of birch mouse, the earliest prehistoric ancestor of the modern-day birch mouse. Named Sicista primus, the new species connects two previously known fossils that are nine million years apart